The present invention relates to a conveyor chain comprising inner chain links and outer chain links which are arranged in alternating succession and which are interconnected by respective chain hinges, a chain hinge comprising a sleeve of the inner chain link and a pin forming part of the outer chain link and extending through the sleeve.
The prior art comprises a plurality of conveyor chains having the above-described structural design. One of these types of conveyor chains is the accumulation conveyor chain. An accumulation conveyor chain comprises, on the one hand, running rollers provided for the purpose of guiding and for engagement with the chain-drive sprockets, and, on the other hand, accumulation rolls which are used as load-carrying rolls and which, in the case of accumulation, guarantee rolling contact with the objects to be transported. There are simple accumulation conveyor chains in the case of which the outer chain link comprises two parallel outer link plates and two pins interconnecting said outer link plates, and the inner chain link comprises two parallel inner link plates and two sleeves interconnecting said inner link plates. Normally, every second sleeve has provided thereon an accumulation roll, which is arranged such that it is freely rotatable. In order to achieve a higher degree of overlap of the accumulation rolls, there is also one variant where the inner chain link is composed of two sleeves and a central link plate which is arranged centrally relative thereto. This variant uses narrower accumulation rolls which are located on the right-hand side of the central link plate in the case of the first sleeve and on the left-hand side of the central link plate in the case of the next sleeve so that the accumulation rolls alternate in a zigzag mode and so that a partially overlapping arrangement is provided. Also in the case of this variant only every second sleeve of one row has arranged thereon an accumulation roll. The use of such conveyor chains is widespread. The chains are normally guided in a special rail system, which can also be used for side bow guidance in connection with special accumulation conveyor chains. In such arrangements problems may sometimes be caused by dust particles penetrating into the rail system. In connection with some types of chains it is already known to provide covers by means of which certain areas of the chain are covered in such a way that an ingress of dust particles is prevented.
It is now the object of the present invention to provide an improved conveyor chain having improved wear properties.
In accordance with the present invention, this object is achieved by the features that at least one brush element is provided, which comprises at least one fastening reception means, and that said brush element is attached via the fastening reception means to an inner chain link and/or an outer chain link such that it is essentially in positive engagement therewith.
By means of this measure, the conveyor chain is provided with an active cleaning function, i.e. it is not only attempted to prevent an ingress of chips by means of a cover, but dirt particles are also actively removed from the chain guiding area. Such brush elements need not be arranged over the entire length of the chain, but it will suffice to position individual brush elements in such a way that the necessary cleaning function is guaranteed. Due to the fact that the fastening reception means is implemented as a push-on reception means (clip-on reception means), standard chains can also be equipped subsequently with this kind of brush elements.
An advantageous embodiment is an embodiment in the case of which the brush element is attached via the fastening reception means to a peripheral area of at least one sleeve of the inner chain link such that it is essentially in positive engagement therewith. This structural design will provide stable fastening.
In accordance with an advantageous embodiment, the brush element may comprises a plastic base member including said at least one fastening reception means, and bristles which are fixedly anchored in said plastic base member. Such plastic base members can be adapted very easily to a great variety of circumstances. Also the areas in which the bristles are anchored can be implemented in different ways. The bristles may, for example, be arranged in oblique, X, parallel and other modes of arrangement. Also the use of different materials and of different geometries of the bristles is imaginable.
In addition, the fastening reception means may be defined by a hole formed in said plastic base member and encompassing the sleeve of the inner chain link in positive engagement therewith. This will normally necessitate that the brush element is already pushed onto the sleeves when the chain is being mounted. A very tightly fitting and firm connection, which can only be released by destruction, is obtained in this way.
It is, however also possible that the fastening reception means comprises a detent means which is in elastic, locking engagement with the sleeve of the inner chain link. Hence, the brush element can be lockingly engaged with various portions of the chain. On the basis of this releasable mode of arrangement, an exchange is possible at any time. Such brush elements can, in principle, be lockingly engaged with the conveyor chain at any suitable location of the conveyor chain.
According to one embodiment, the detent means can be defined by a detent groove provided with a resilient boundary area on at least one side thereof, the detent groove encompassing the sleeve of the inner chain link over an angular area of more than 180xc2x0. A detent groove of this type will guarantee a tilt-proof arrangement e.g. over the whole length of the sleeve. When an appropriate material is chosen for the brush elements, suitable locking forces will be obtained when the chain is in operation so that the brush element cannot become detached inadvertently.
In addition, the brush element may comprise a pair of fastening reception means, the brush element may be arranged as a bridging unit between the two sleeves of an inner chain link, and each fastening reception means of the pair of fastening reception means may be attached to one of the sleeves of the inner chain link. This double attachment of the brush element provides reliable guidance and the best possible fixing of the brush element to the other elements of the chain. Furthermore, the gap between two sleeves is closed so that, in addition to the cleaning function of the bristles, also a cover function for covering this gap is fulfilled.
The conveyor chain can be implemented as an accumulation conveyor chain including accumulation rolls which are arranged on sleeves of the inner chain links, some accumulation rolls being replaced by brush elements. The brush elements are arranged such that a high load-carrying capacity of the accumulation rolls is still given, as far as possible, and that only individual accumulation rolls are replaced by brush elements. The number of brush elements depends on the cleaning function which is to be achieved.
In accordance with an advantageous embodiment, at least the bristles of the brush elements may project beyond the accumulation rolls in certain areas, when the conveyor chain is in operation. This will guarantee that a guide rail is swept clean. Due to the fact that the bristles project beyond the accumulation rolls, also the contact force with which the bristles are pressed onto a surface to be cleaned can be adjusted.
In addition, the inner chain link may comprise two sleeves and a centrally pressed-on central link plate interconnecting these two sleeves, and the outer chain link may comprise two pins and two outer link plates which are arranged in parallel and which interconnect these pins, a brush element being arranged in the space between an outer link plate and the central link plate. This embodiment of a conveyor chain permits the use of very narrow brush elements because said brush elements are arranged only in the space between the central link plate of the inner chain link and an outer link plate of the outer chain link.
A further embodiment is so conceived that two brush elements are implemented such that they form a structural unit with a central slot and that the central link plate is accommodated in said central slot. It follows that the brush unit implemented in this way covers the central link plate at the lower end thereof. It is also possible to use the central link plate for further fixing.
In accordance with a preferred embodiment, the pins of the outer chain links may project laterally and a running roller may be arranged on each of these projecting end portions. The actual guiding function of the conveyor chain is then executed via these running rollers. The spaces between the running rollers are normally also engaged by the driving sprockets so that the central area of the chain is reserved to the accumulation rolls and the brush elements.
In addition, the present invention may relate to a brush element for a conveyor chain according to one of the claims 1 to 12, said brush element comprising at least one fastening reception means which is adapted to be pushed onto at least one sleeve of an inner chain link of the conveyor chain.